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Using Water / Methanol Injection


Well-known user
Back in the mid 1970s I used to race every weekend if it be Auto-crossing or Drag Racing
As happens with any type of heat the engine reduces it's performance levels.

I did a lot of searching and then thought "hell if the USA and UK military can do this, so can I"
Plus we old timers recall back in early 1980s even GM sold some cars that had w/meth installed on them to reduce knock
but car owners were too lazy to refill the w/meth tanks

And that was in all their testing they found if they injected a 50/50% mix of water and Methanol under pressure
into the air intake of war airplanes performance was increased

Back then with a C3 which had a Carb I decided to install a small injector pointing down the throat of my Holly 650
and used a pump output of 220 PSI and used Vacuum as a trigger point to force that flow through a w/meth injector
Ended up working well and even then allowed more total timing

Under pressure when the water/Meth is forced through a small nozzle the 2 fluids then turn to a vapor
The water part reduced the incoming air temp leaving a better burn in cylinder and the Methanol not only
raises the fuel's octane but overall a cooler charge to the cylinders so that the molecules per charge are tighter and
burns really nice.
This also reduces engine knock so within a tune higher timing can be commanded and engine sees both HP/Tq gains and allows for a
leaner AFR e commanded via a tune.
Also the water vapor cleans the cylinder walls, top of pistons and valve face.
I have used water/Meth in 10 Corvettes I have owned including the King of the Hill C4 ZR-1 using the Lotus engine ( we owned at time at GM)
and including engines of today.
I have Corvette owners using them even on today's C7s

Not sure what you use in the UK but here in USA windshield waster fluid (winter version) is only water and 38% Methanol
In fact we use that in cooler weather on street driving and costs like $2 a gallon
Other wise for hot or racing use 50/50% of water meth. Both UK and USA testing back in WW-II found no positive to use more then 50% Methanol
Since as mentioned windshield washer, you could also use that tank for cleaning window and supplying the water/meth to injector pump

Today easy, a nozzle can be installed into the airbridge with nozzle facing into throttle-body and either using MAP as a trigger or buy a w/Meth adjustable controller
My 1999 has used w/Meth since 2003 and looking inside cylinders/piston tops are very clean to this day.

Little bit of W/Meth info '
What are the benefits of Water/Methanol injection?
1. Low cost - where else can you get up to 60HP.
2. More power than other means of detonation control.
3. Efficiency - leaner air fuel ratio can be utilized for normal operation.
4. Greatly increases air charge densities for huge horsepower increases.

W/Meth Benefits (Diesel) or with Boost

1. Greatly reduced EGT’s. Decreases of 250 degrees F are common using a 50/50% Methanol /Water mix.
This prevents the usual problems associated with high exhaust car temperatures - rings sticking, holed pistons, etc.
2. Low cost power - where else can you get 30-60 HP for approximately $500 along with reduced EGT's.
3. Greatly increased air charge densities - 3-5 psig boost increases are common.
4. Great for towing - more power/cooler EGT's to haul the heaviest loads.
3. Why not use a windshield washer pump?
Water/Methanol must be injected at above 50psi to properly atomize.
Lower than 50psi causes greatly reduced air charge cooling as the result of larger droplets and their reduced total surface area.
4. Why methanol?
Methanol is a high octane fuel that is extremely resistant to detonation with an excellent cost/benefit ratio. ($1.50 - $2.00 per gallon.)
Its high latent heat of vaporization also makes it an excellent air charge cooler which means a denser mixture and more horsepower.
Because of these facts, it is a better anti-detonant than ethanol or iso-propanol although they will work in a pinch.
It has however only about 60% of the energy content of gasoline by volume so about twice as much is used to make similar power if used as a straight fuel.

5. How much Water/Methanol?
To prevent detonation, the ratio of Water/Methanol to gasoline is roughly 1 to 5 in gasoline applications- 1 to 4 in diesel. In practice, you give it as much water / methanol as it takes to eliminate detonation without quenching combustion.
The amount depends on the onset RPM of injection, the octane of the gasoline, fuel/air ratio, cylinder head type, even the weather conditions.
Your engine is actually pretty tolerant of extra water vapor, you will know it's too much when the engine misses and loses power.
6. Where can I purchase Methanol?
Methanol can generally be purchased where racing fuels are sold.
Also, most gas line dryers like "Heat" are simply Methanol. Suppliers of industrial chemicals can also supply Methanol usually at a higher price than fuel suppliers.
If all else fails, most windshield washer fluids are up to 40% Methanol and 58% water.
Methanol can be purchased on the web
7. How long will a tank (2 qts.) last?
In high boost/high horsepower application, a full blast 1/4 mile run will utilize as much as 1/8 tank.
A larger tank should be considered if over 9psi boost is utilized in road racing where a tank can be used in as few as 6 - 2 mile/ full tilt laps. Under normal street use in a 400 HP Corvette, a tank usually lasts about 500 miles.
Two reservoirs can be used for 1-gal total capacity if desired. Turbo diesels use more qty. and usually utilize the existing windshield washer reservoir (over 4 qts. in most cases) or the new 8-gal reservoir upgrade. More will always be used when the system is first installed, less when the novelty wears off.
8. Can I use windshield washer fluid?
Although most contain some glycol and detergent, most windshield washer fluids are up to 50% alcohol (methanol, ethanol, isopropanol) and make an excellent Boost Cooler. Try to find one that indicates "contains methanol".
9. At what boost level do I introduce Water/Methanol?
Centrifugal superchargers/large turbos: Generally, at 50% of peak boost the recommended quantity should be introduced. Positive displacement superchargers/ fast spooling turbos: injection should occur at or near peak boost to avoid combustion quench since peak boost occurs so fast.
10. What ratio of Water/Methanol is recommended?
A 50/50 ratio is recommended. This has been demonstrated to be the best for charge/air cooling, excellent detonation control, and controlling cylinder temperature. This includes diesel applications where water conditions the combustion of the methanol so combustion timing isn't affected.

11. Will water/methanol harm my engine?
In theory, at recommended quantities, most of the mixture is evaporated before it hits the combustion chamber. Also, injection only takes place at high boost levels minimizing cylinder wash concerns. Engines that have been torn down after two years of water/methanol usage have shown no wear issues only clean combustion chambers. In fact, water/methanol reduces the probability of engine destroying detonation. Think of it as an insurance policy against detonation.
12. Can W/Meth be applied to naturally aspirated and Nitrous engines? YES

1.Naturally aspirated/high compression engines:
In this application, water/methanol injection allows the use of pump fuel in all but the most extreme situations which effects tremendous cost savings as well as horsepower increases due to air density increase and realized timing potential. The system is activated by a throttle switch so that injection takes place only during high engine loads when needed.
2. NOS engines: with NOS, water/methanol injection allows the use of full timing even with large (250HP+) quantities. Injection is controlled by the same means that controls NOS injection.
3. Naturally aspirated/stock compression: With naturally aspirated engines with less than 10:1 compression, water/methanol is used typically in warm climates to get the intake temps back to 60°f.
Benefits include: 10-15 HP increases from air density increases and full timing, Increased gas mileage, and carbon free combustion chambers. Activation is by a throttle switch adjusted for onset engine load. With this application, the nozzle is sized so that no more than 10% of total fuel consumption at peak flywheel HP is injected.

Fishy Dave

CCCUK Member
I used water meth injection in my Lotus Elise turbo race car. It made a massive difference to intake temps and heat soak. I used a system linked to the maf sensor.